In an enterprise oriented search engine, such as ESP (Enterprise Search Platform), search that takes user's access right into account is necessary in view of ensuring security. The ESP transversely searches for information on the Internet and that on intra-enterprise information processing systems, and is also termed ‘intra-enterprise integrated search platform’. Control of access right to a file (document) or folder (directory) is performed using ACL (Access Control List).
A function required of ACL search is to present, as a result of search, only those documents to which a user has access rights. The following describes the ACL search.
Patent Document 1, for example, discloses an information search apparatus which takes access right that is set in a document into account to perform search. Specifically, the information processing apparatus includes an index storage means which correlates the information acquired by a file information acquisition means with the information acquired by a right information acquisition means to store the resulting correlated information as an index. The right information acquisition means acquires right information indicating a user that is allowed to access a file. The information processing apparatus also includes a search condition formula generation means that generates a search condition formula from the user information specified by a user identifying means and from a keyword and a search means that searches an index which is in meeting with the search condition formula from the index storage means.
FIG. 1 is a diagram illustrating a configuration that holds the ACL right information beforehand on a search server side. This configuration corresponds to the configuration disclosed in the above mentioned Patent Document 1. Non-Patent Document 1 also shows a similar configuration. FIGS. 1 and 2 are newly drawn by the present inventors to illustrate the background of the present invention.
A search server 1 acquires beforehand ACL information (_acl) 5 of a document from a repository 3, in which the ACL information is stored. The search server 1 stores the so acquired ACXL information in e.g., a database, not shown. The search server 1 matches an index 4, which corresponds to a search condition, to the ACL information (_acl) 5 (e.g., AND operation), and outputs a document, to which a user, who has issued a search request, has an access right, as a search result to the user. An authentication server 2 checks whether or not a user is a registered one by matching of a password the user entered when logging in. The authentication server 2 is such as ADS (Active Directly Server) or the Windows (registered trademark) Server.
FIG. 2 shows how the search server 1 checks to see whether or not there exist an access right when outputting a search result. In outputting the search result document in response to a search request, an ACL checker 6 confirms an access right to document(s) of interest, stored in the repository 3, and selects document(s) to which the user has an access right to output the document(s) selected to a search result list. With this technique, the search result that reflects the latest ACL may be obtained at all times. Unlike the configuration of FIG. 1, it is unnecessary to hold the ACL information in the search server 1.
Patent Document 1:
    JP Patent Kokai Publication No. JP-P2001-344245APatent Document 2:    International Patent Kokai No. 2008/044542 pamphlet (WO 2008/044542A1)Non-Patent Document 1:    Christopher D. Manning, Prabhakar Raghavan and Hinrich Schutze, Introduction to Information Retrieval, Cambridge University Press, 2008, pp. 61-77, <URL>http://www-csli.stanford.edu/-hinrich/Information-Retrieval-book.html Retrieved on November 2008